Biological Deep Displacement Control Technology

Traditional indigenous microbial oil displacement technology use water-soluble nutrition system, such as nitrogen, phosphorus salt system, low sugar system, and supplement quantitative air to achieve the activation of reservoir good nutrient flora and biodegradation of crude oil, this system mainly emphasizes the role of' drive', while ignoring the role of' plug'.Water - soluble nutrients will flow along the high permeability area when injected into the reservoir, with short retention time in the reservoir, low utilization of microorganisms, and short interaction time between biological products and reservoir rocks and fluids. this is the main reason why the original microbial flooding technology is not obvious or slow to take effect in the field.

Bio - deep profile control and flooding technology is a new microbial oil extraction technology which combines with “adjust”and “displacement”. The nutritional system technology is compounded by using a plurality of natural products as raw materials, and is a novel powder or granular nutritional system ( the main ingredients are cellulose, and starch polysaccharide ).

Starch - cellulose - based nutritional system is a cheap and easily available natural polysaccharide nutritional agent, which has rich components, high activation efficiency to the original flora, and it is easy to suspend in water.

The system effectively overcomes the defects of single component and easy loss of the conventional nitrogen and phosphorus salt systems; the system not only has the function of improving the oil washing efficiency, but also has the obvious stratum retention effect due to the fact that the nutrient is particulate matter, effectively enlarges the microbial fermentation action range, has quick field effect and slow decline, and can greatly improve the oil displacement effect.

The technology utilizes the plugging effect of the granular nutrient in the formation ( or the interception effect of the porous medium on the nutrient ), greatly prolongs the retention time of the nutrient in the formation. It enables microorganisms fully utilize the nutrient to generate products such as surface active substances, biological gas, and it has better emulsification effect on crude oil under the condition of the oil reservoir, these products can improve the 'displacement' effect.

Meanwhile, due to the retention function of the nutrient in the stratum, the microbial cell body can be attached to the surface of the nutrient particles for propagation and growth. A large number of biomembrane ( including cell body aggregates and extracellular polysaccharide metabolites, etc. ) are generated on the surface of the particles, and the formation of the biomembrane has an important strengthening effect on the subsequent continuous propagation of microorganisms and the plugging effect of the system, so that the water flooding swept volume can be effectively improved. Laboratory heterogeneous flooding model evaluation experiments show that the recovery rate can be increased by 12 - 20 %.

The technology is suitable for conventional waterflooding reservoir, high temperature and high salt reservoir. It has wide application range and not limited by reservoir temperature and water quality ( mineralization degree ), it has greatly reduced cost compared with conventional chemical flooding control technology.

The characteristics of the biological deep displacement control technology has obvious spread and volume effect of expanding fermentation in the formation, it has obvious effect on the activation of reservoir microorganisms, and it is not affected by reservoir temperature and formation water properties. It has wide and easily available nutrient sources, low cost, environment-friendly and it has no secondary pollution.